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https://issues.apache.org/jira/browse/ZOOKEEPER-1367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13190101#comment-13190101
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Jeremy Stribling commented on ZOOKEEPER-1367:
---------------------------------------------

There are no config file -- we embed Zookeeper into our application framework 
and set up things through code.  I'm not sure what you're looking for exactly 
-- I've given the IPs and ZK ids of the servers above.  Besides that, we set up 
specific client, election, and server ports (those shouldn't matter), and put 
the snapshot and log directories together in the same place (I know, I know -- 
we're working on teasing them apart, but it's not currently a bottleneck for 
our application).  Tick time and election algorithm are the default.  Clients 
request a session timeout of 1 second, which means they get the default timeout 
of 2 times the default tick time.  Let me know if you are asking about some 
other config value.

I certainly wouldn't be surprised if it's a problem with our use of Zookeeper, 
since we use it in a non-traditional way, but this scenario was so simple that 
nothing jumps to mind immediately that could cause it.
                
> Data inconsistencies and unexpired ephemeral nodes after cluster restart
> ------------------------------------------------------------------------
>
>                 Key: ZOOKEEPER-1367
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1367
>             Project: ZooKeeper
>          Issue Type: Bug
>          Components: server
>    Affects Versions: 3.4.2
>         Environment: Debian Squeeze, 64-bit
>            Reporter: Jeremy Stribling
>            Priority: Blocker
>             Fix For: 3.4.3
>
>         Attachments: ZOOKEEPER-1367.tgz
>
>
> In one of our tests, we have a cluster of three ZooKeeper servers.  We kill 
> all three, and then restart just two of them.  Sometimes we notice that on 
> one of the restarted servers, ephemeral nodes from previous sessions do not 
> get deleted, while on the other server they do.  We are effectively running 
> 3.4.2, though technically we are running 3.4.1 with the patch manually 
> applied for ZOOKEEPER-1333 and a C client for 3.4.1 with the patches for 
> ZOOKEEPER-1163.
> I noticed that when I connected using zkCli.sh to the first node (90.0.0.221, 
> zkid 84), I saw only one znode in a particular path:
> {quote}
> [zk: 90.0.0.221:2888(CONNECTED) 0] ls /election/zkrsm
> [nominee0000000011]
> [zk: 90.0.0.221:2888(CONNECTED) 1] get /election/zkrsm/nominee0000000011
> 90.0.0.222:7777 
> cZxid = 0x400000027
> ctime = Thu Jan 19 08:18:24 UTC 2012
> mZxid = 0x400000027
> mtime = Thu Jan 19 08:18:24 UTC 2012
> pZxid = 0x400000027
> cversion = 0
> dataVersion = 0
> aclVersion = 0
> ephemeralOwner = 0xa234f4f3bc220001
> dataLength = 16
> numChildren = 0
> {quote}
> However, when I connect zkCli.sh to the second server (90.0.0.222, zkid 251), 
> I saw three znodes under that same path:
> {quote}
> [zk: 90.0.0.222:2888(CONNECTED) 2] ls /election/zkrsm
> nominee0000000006   nominee0000000010   nominee0000000011
> [zk: 90.0.0.222:2888(CONNECTED) 2] get /election/zkrsm/nominee0000000011
> 90.0.0.222:7777 
> cZxid = 0x400000027
> ctime = Thu Jan 19 08:18:24 UTC 2012
> mZxid = 0x400000027
> mtime = Thu Jan 19 08:18:24 UTC 2012
> pZxid = 0x400000027
> cversion = 0
> dataVersion = 0
> aclVersion = 0
> ephemeralOwner = 0xa234f4f3bc220001
> dataLength = 16
> numChildren = 0
> [zk: 90.0.0.222:2888(CONNECTED) 3] get /election/zkrsm/nominee0000000010
> 90.0.0.221:7777 
> cZxid = 0x30000014c
> ctime = Thu Jan 19 07:53:42 UTC 2012
> mZxid = 0x30000014c
> mtime = Thu Jan 19 07:53:42 UTC 2012
> pZxid = 0x30000014c
> cversion = 0
> dataVersion = 0
> aclVersion = 0
> ephemeralOwner = 0xa234f4f3bc220000
> dataLength = 16
> numChildren = 0
> [zk: 90.0.0.222:2888(CONNECTED) 4] get /election/zkrsm/nominee0000000006
> 90.0.0.223:7777 
> cZxid = 0x200000cab
> ctime = Thu Jan 19 08:00:30 UTC 2012
> mZxid = 0x200000cab
> mtime = Thu Jan 19 08:00:30 UTC 2012
> pZxid = 0x200000cab
> cversion = 0
> dataVersion = 0
> aclVersion = 0
> ephemeralOwner = 0x5434f5074e040002
> dataLength = 16
> numChildren = 0
> {quote}
> These never went away for the lifetime of the server, for any clients 
> connected directly to that server.  Note that this cluster is configured to 
> have all three servers still, the third one being down (90.0.0.223, zkid 162).
> I captured the data/snapshot directories for the the two live servers.  When 
> I start single-node servers using each directory, I can briefly see that the 
> inconsistent data is present in those logs, though the ephemeral nodes seem 
> to get (correctly) cleaned up pretty soon after I start the server.
> I will upload a tar containing the debug logs and data directories from the 
> failure.  I think we can reproduce it regularly if you need more info.

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